OP0246 TO SCAN OR NOT TO SCAN (BOTH HIPS) – A BRISTOL EXPERIENCE
Authors: A. Anilkumar, S. Saeed, E. Elsayed, C. N. R. Jayatilleke, S. Webber, M. A. Roy
Journal: Annals of the Rheumatic Diseases (2022)

Background The current International Society of Clinical Densitometry (ISCD) recommendation for bone densitometry practice is that single hip measurement is sufficient in clinical practice, as there is overall a good correlation between the two hip bone mineral densities (BMD) (1) (2). However, discordance in individual T- scores and BMD between the 2 hips due to increasing age and osteoarthritis (3)-(5) is well recognised. Objectives We aimed to identify whether discordant hip BMD values would lead to differences in the FRAX risk assessment score between the two hips, and thereby impact treatment decisions in clinical practice. Methods We looked at all DXA scans performed at our centre for 2 months between 23/7/21 and 23/9/21. Cases in which both hips were scanned and anti-resorptive treatment was advised were included in our study. The femoral neck with the lower BMD is used to calculate the FRAX score and this was referred to as the ‘reported’ hip. The FRAX score for ‘reported’ and ‘unreported’ hip were calculated and the T-score of the spine was also noted. Our local treatment threshold is set at 20% for a major osteoporotic fracture and 5% for hip fracture. Cases of difference in scores crossing the 20%/5% FRAX threshold were highlighted and reviewed in more detail. Results DXA scans were performed in 328 patients over the 2 month period, of which 201 patients had both of their hips scanned. Of these, 50 patients were advised to start anti-resorptive treatment. The majority of the treatment decisions (60%; 30/50 cases) were based on the hip/femoral neck BMD value, while 40% (20/50 cases) were based on the spine T-score. Where the treatment decision was based on hip/femoral neck BMD, 20% (6/30 cases) were found to have a FRAX risk above the treatment threshold at one hip only, meaning that treatment may not have been offered if both hips had not been scanned. Similarly, where treatment was advised based on spinal T-scores, 20% (4/20 cases) had a FRAX risk above treatment threshold at one hip only. Mean age across these 10 cases with a discordant FRAX risk between the two hips was 72 years (range 59 – 83); 80% (8/10) were female. Steroid use and chronic inflammatory co-morbidities were the predominant indications for these DXA Scans. Conclusion A significant proportion of patients in our cohort (20%; 10/50) may not have been offered treatment if only one hip was scanned. Scanning both hips does not require much additional time and can help mitigate the risk of undertreating patients. The recommendation for best practice for DXA BMD measurements should be reviewed to consider lumbar spine and dual hip BMD as standard of care. References [1]E. Michael Lewiecki, Nelson B. Watts, Michael R. McClung, Steven M. Petak, Laura K. Bachrach, John A. Shepherd, Robert W. Downs, Jr., Official Positions of the International Society for Clinical Densitometry, The Journal of Clinical Endocrinology &amp; Metabolism , Volume 89, Issue 8, 1 August 2004, Pages 3651–3655, https://doi.org/10.1210/jc.2004-0124 [2]Rao AD, Reddy S, Rao DS. Is there a difference between right and left femoral bone density? J Clin Densitom. 2000 Spring;3(1):57-61. doi: 10.1385/jcd:3:1:057. PMID: 10745302. [3]Chen W, Khan Z, Freund J, Pocock N. Dual Hip DXA. Is it Time to Change Standard Protocol? J Clin Densitom. 2021 Jul 24:S1094-6950(21)00060-3. doi: 10.1016/j.jocd.2021.07.006. Epub ahead of print. PMID: 34391641. [4]Mounach A, Rezqi A, Ghozlani I, Achemlal L, Bezza A, El Maghraoui A. Prevalence and Risk Factors of Discordance between Left- and Right-Hip Bone Mineral Density Using DXA. ISRN Rheumatol. 2012;2012:617535. doi: 10.5402/2012/617535. Epub 2012 Jun 17. PMID: 22778990; PMCID: PMC3384949. [5]Nishizawa K, Harato K, Morishige Y, Kobayashi S, Niki Y, Nagura T. Correlation between weight-bearing asymmetry and bone mineral density in patients with bilateral knee osteoarthritis. J Orthop Surg Res . 2021;16(1):102. Published 2021 Feb 2. doi:10.1186/s13018-021-02252-5. Disclosure of Interests Aishwarya Anilkumar: None declared, Sadaf Saeed: None declared, Ehsan Elsayed: None declared, Chandrin N. R. Jayatilleke: None declared, Stuart Webber: None declared, Mathew A. Roy Consultant of: Worked as a paid consultant for Kyowa Kirin.